[pvrusb2] /dev/vbi0 missing?

[Mike Isely]

On Sat, 16 Sep 2006, Michael Caldera wrote:

> I seem to be at my wit's end here. I'm a linux newbie, and with some stroke
> of luck, i think i actually manage to install the driver.
> 
> I installed standalone driver, and i have extracted the firmware and placed
> it in /lib/firmware. did all the modprobing, and i do now have /dev/video0 .
> I tried
> 
> cat /dev/video0 > /tmp/test.mpg
> 
> and it seems to be streaming data...albeit, static...but i think it's cause
> it's not set to a channel properly.
> 
> when i use mplayer /dev/video0 i also get the same effect.

It probably isn't tuning properly, as you suspect.  Using mplayer it's 
going to be tuned to whatever it was set to before mplayer was started, 
i.e. mplayer can't control the tuning.  In a situation like this you can 
use the sysfs interface to control the tuning aspects.

You need to make sure that the correct video standard has been set and 
that you're tuned to a valid frequency.

> 
> i do get errors however when i run them from terminal
> ____________
> Cannot seek backward in linear streams!
> Seek failed
> Cannot seek backward in linear streams!
> Seek failed

That's not necessarily a problem.  I've seen it here as well.  My 
suspicion is that when mplayer starts it's getting into the middle of the 
stream and the first few frames of video data can't be constructed becase 
they're not i-frames (and thus mplayer wants to seek backwards to find the 
missing previous i-frame).  This will clear itself in a second or three 
once the next i-frame is seen.


> Win32 LoadLibrary failed to load: avisynth.dll,
> /usr/lib/codecs/avisynth.dll, /usr/lib/win32/avisynth.dll,
> /usr/local/lib/win32/avisynth.dll

That's an mplayer config issue.  It's not fatal to the driver.

> ___________
> open: No such file or directory
> Couldn't open: /dev/mga_vid
> open: No such file or directory
> Couldn't open: /dev/mga_vid
> [VO_TDFXFB] Can't open /dev/fb0: No such file or directory.
> ____________

I've never seen these before, but it could be just due to my mplayer 
configuration.

If you can cat /dev/video0 and get data from it then you've gotten past 
the most difficult parts of the setup.  The fact that you're getting bytes 
means that the video pathway is working - it just isn't getting anything 
worth displaying.

Another thing you can do in a pinch if you have a DVD player, VCR or video 
camera is try the composite or s-video input.  Then you bypass the tuner 
and can prove to yourself that everything else is working.  You'll need to 
tell the driver to switch the input selection; again that can be done 
easily at the shell prompt via the sysfs interface.

Another application you can try is xawtv.  Use any 4.x version (previous 
to that xawtv didn't support mpeg2 decoding), compile it for mpeg2 and mp3 
support.  Then you can use xawtv to scan and find live channels.

> 
> also, when i use TVtime, it's looking for
> /dev/dvi0

TVtime doesn't support mpeg2 decoding.  It wants to access a dumb 
framebuffer device, which the pvrusb2 is not.  Unless something has 
changed there, you won't get far with TVtime.


> 
> 
> any help? i've been working on this for 3 days now...seems like i'm really
> stuck. (also please keep in mind i'm a linux newbie)

I think your root problem here is that you don't have a valid frequency 
tuned.  Everything else you describe suggests that the driver is installed 
and working.  If you know of a specific frequency you can test with, just 
set it via sysfs and try mplayer again.  Otherwise you can try out xawtv.  
I recommend you look again at the usage page:

http://www.isely.net/pvrusb2/usage.html

There's also a copy of it in the doc subdirectory of the standalone 
snapshot.  Using the sysfs interface is a quick and easy way to see what's 
going on in the driver - look at the description of the sysfs interface as 
well.

Regarding the subject line - the pvrusb2 driver doesn't do vbi so you 
won't see a vbi device node.

  -Mike


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